Laser machining systems and methods are commonly used to machine various types of materials and structures. Such laser machining systems and methods may provide a number of advantages including lower manufacturing costs, increased throughput and production yield, and improved quality. In the area of solar panels, for example, the advantages of laser machining could significantly enhance the efficiency and viability of solar energy technology.
In the manufacture of thin film photovoltaic (PV) solar panels, laser machining techniques may be used to scribe the various thin film layers in a panel to form electrically connected cells. In one type of PV solar panel, three layers are deposited to form the panel and lines are scribed after each new deposition. The area on the panel including these lines is considered a wasted area that does not contribute to solar energy conversion. Thus, the lines should be straight and aligned accurately to minimize this wasted area and to provide the best efficiency. High scribing speeds and increased throughput are also desirable. Providing accurate high speed scribing of thin film PV solar panels (and other similar structures) presents a number of unique challenges.
In particular, vibrations and/or forces generated by and/or transmitted to the laser machining system may adversely affect the machining precision and speed. Passive isolation techniques may be used to decouple the processing area of a machine from the floor. Isolators are often placed between the machine frame and a granite base that supports the processing area components. However, the laser machining of scribe lines in solar panels involves the translation of the optical head and/or the solar panel. When these components move relative to the granite base, forces are transmitted to the granite base and reaction forces can cause parasitic errors in the precision of the machining. In other words, the granite base sways back and force and the reaction forces may be transmitted back into the optical head. Waiting for these reaction forces to subside can significantly slow the machining process. Although various force transfer and cancellation techniques have been used with motion stages, these existing techniques may not be suitable for laser machining applications in which high speed, accuracy and high throughput is desired.